Microwave Dielectric Properties of (1 – x )(Al _1/2 Ta _1/2 )O ₂ – x (Mg _1/3 Ta _2/3 )O ₂ Ceramics

Abstract

The microwave dielectric properties of (1 – x )(Al 1/2 Ta 1/2 )O 2 – x (Mg 1/3 Ta 2/3 )O 2 (0 ≤ x ≤ 1.0) ceramics were investigated. (Al 1/2 Ta 1/2 )O 2 and (Mg 1/3 Ta 2/3 )O 2 had orthorhombic and tetragonal structure, respectively. As (Mg 1/3 Ta 2/3 )O 2 concentration increased, (1 – x)(Al 1/2 Ta 1/2 )O 2 – x (Mg 1/3 Ta 2/3 )O 2 transformed to tetragonal structure. Specimens having a tetragonal single phase could be obtained for x > 0.6. As (Mg 1/3 Ta 2/3 )O 2 concentration increased, the grain size, dielectric constant (ɛ r ) and quality factor ( Q ) significantly increased, and the temperature coefficient of resonant frequency (τ f ) changed from a negative to a positive value. A τ f of 0 ppm/°C was realized at x = 0.65 and the Qf o value and ɛ r for this composition were 112 470 GHz and 26.1, respectively. The relationship between microstructures and dielectric properties was also investigated.